# Elementary Matrices

• Apr 13th 2007, 09:05 AM
DivideBy0
Elementary Matrices
If the sales matrices for January and March (with twice as many cars of each model sold in February as January) had been
.[1 0 0], and [2 1 0]
.[4 2 3]........[6 1 4] respectively, find the sales matrix for the first quarter of the year.

I figured that the quarter year sales would be 2*January + March = [4 .1.. 0]
.................................................. .........................................[14 5 10]

.................................................. ...[18 7 13], why is this? :(
• Apr 13th 2007, 09:20 AM
Soroban
Hello, DivideBy0!

You misread that February phrase . . .

Quote:

If the sales matrices for January and March (with twice as many cars
of each model sold in February as January) had been:
.[1 0 0], and [2 1 0]
.[4 2 3]........[6 1 4] respectively, find the sales matrix for the first quarter of the year.

The total is: .[Jan] + 2·[Jan] + [Mar]
Code:

```  Jan      Feb      Mar |1 0 0|  |2 0 0|  |2 1 0| |    | + |    | + |    | |4 2 3|  |8 4 6|  |6 1 4|```